Optimizing drip fertigation management based on yield, quality, water and fertilizer use efficiency of wine grape in North China

Drip fertigation is an advanced technology combining micro-irrigation with fertilization, which is conducive to deliver water and nutrients to crops or fruit trees synchronously. To optimize drip fertigation scheduling for wine grape in North China, a three-year field experiment was conducted to study the effects of irrigation and fertil-ization quota on yield, berry quality, water use efficiency (WUE) and partial factor productivity of fertilizer (PFPF). Nine treatments were set up based on the combinations of three irrigation levels and three fertilization rates. The three irrigation levels were 100 % (IH), 80 % (IM) and 60 % (IL) of the designed irrigation quota, i.e., 25, 20 and 15 mm per irrigation event. The three fertilization rates were 100 % (FH), 80 % (FM) and 60 % (FL) of the compound water-soluble fertilizer amount locally recommended, i.e., 630, 504 and 378 kg ha-1 yr- 1. Both irrigation and fertilization had a significant effect on yield. Irrigation also significantly affected titratable acid and sugar-acid ratio. Averaged across the years and fertilization rates, compared with IH treatment, IM treatment decreased titratable acid by 3.3 % and increased sugar-acid ratio by 12.2 %; IL treatment decreased titratable acid by 10.7 % and increased sugar-acid ratio by 20.0 %. FM treatment presented the richest anthocyanins and condensed tannins among the three fertilizer rates. IWUE was significantly increased with the decrease of irri-gation amounts; WUE and PFPF reached the maximum in IM treatment. The decrease of fertilizer rates signifi-cantly increased PFPF but was not beneficial for WUE. Interaction effects between irrigation and fertilization were only significant on PFPF. Assessed by gray relational analysis (GRA), technique for order preference by similarity to ideal solution (TOPSIS) and combinational evaluation method (CEM), the combinational evaluation value (Qi) of IMFM treatment (moderate water and fertilizer, 20 mm per irrigation event combined with 504 kg ha-1 yr- 1 compound water-soluble fertilizer) was the highest on the whole, indicating that IMFM treatment was the optimal treatment which could balance yield, quality and water-fertilizer use efficiency. These results may provide a benchmark for wine grape cultivation under drip fertigation in North China and other regions with similar environmental conditions.